Hydraulic support



Dec. 12, 1961 w. wlLKENLoH ErAL 3,012,404

HYDRAULIC SUPPORT Filed Dec. 13, 1956 2 Sheets-Shree?I 1 .Im/enfans h/{Hunlgh .nl Erick Taegrf Dec. 12, 1961 w. wlLKENLoH ETAL 3,012,404-

HYDRAULIC SUPPORT Filed Deo. l5, 1956 2 Sheets-Sheet 2 United States Patent Olice 3,012,404 Patented Dec. 12, 1961 The present invention relates to supporting structures and more particularly to hydraulic supporting structures of the type which may be used, for example, as pit props in mine galleries.

With hydraulic supporting arrangements of this type A it is customary to enable the pit props or the like to co1- lapse by directing liquid from pressure chambers thereof to a suitable reservoir. Howeyer, the speed and eliiciency of the collapse of such hydraulic arrangements is not very high because of the fact that only a small cross section of ilow is provided by opening a valve in order to collapse the support structure and also collapse is retarded by the rictional engagement between relatively sliding parts. Furthermore, air becomes trapped Wi-thin the reservoir to which a pressure liquid is returned so that the collapse of the structure is also retarded in this way.

One of the objects of the present invention is to provide a hydraulic collapsible and expandible supporting arrangement which is capable of being quickly and efficiently collapsed.

Another object of the present invention is to providel an arrangement which guarantees that a reservoir to which pressure liquid is returned during collapse of the supporting arrangement is at less than atmospheric pressure so that a quick efficient flow of the liquid back to the reservoir during collapse of the supporting arrangement is assured.

lt is also an object of the present invention to adapt the principle of the invention -for use either with individual supporting units or with an arrangement of a group of supporting units.

An addititonal object of the present invention is to provide structure capable of accomplishing all of the above objects and at the same time composed of simple and ruggediy constructed elements which are very reliable in operation.

With the above objects in view, the present invention mainly consists of a hydraulic supporting arrangement which includes an expandible and collapsible means having a collapsed rest position and an expanded supporting position, this means including a pressure chamber to which liquid is supplied during expansion and from which liquid ows during collapse of the expandible and collapsible means. A reservoir is provided for the pressure liquid, and a pump means communicates with the reservoir and with the pressure chamber for pumping liquid .from the reservoir to the pressure chamber in order to expand the expandible and collapsible means. A conduit means communicates with the pressure chamber and with the reservoir, and a valve means is in the conduit means for closing and opening the same so that when the valve means opensrthe conduitv means the pressure liquid may ow from the pressure chamber back to the reservoir to enable the collapsible and expandible means to collapse. This reservoir has its interior at less than atmospheric pressure during the collapse of the expandible and collapsible means.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages-thereof, will be best understood from thefollowing description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. l is a sectional elevational view of an embodimeut of an individual supporting arrangement according to the present invention; and

FIG. 2 diagrammatically illustrates an arrangement where a plurality of collapsibleV and expandible supporting units cooperate with la single reservoir and pumping assembly. j

The structure shown in FIG. 1 may be used as a pit v prop, and this hydraulic supporting arrangement which is shown in FIG. l includes an inner tubular member 1 and au outer tubular member 3 within which the inner member 1 is slidable. The bottom end of the inner memf ber 1 is closed by -a piston 2 which slides along the inner surface of the outer member 5 for the purpose of collapsing or expanding the supporting structure by changing the length thereof. When the supporting structure is in its collapsed rest position, the pressure liquid 4, which may be a suitable oil or the like, is located Within the reservoir 5 formed by the hollow interior of the inner member 1. A pump means 6 is located in the interior of the inner. member 1 for the purpose of pumping liquid frorn'the reservoir 5 to the pressure chamber 7 located in the interior of the outer member 3 beneath the piston 2 in order to move the inner member 1 outwardly of the outer member 3. The pump 6 is operated by an eccentric 14 carried by the inner member 1. The eccentric 14 may Ibe turned by applying a crank to the noncircular portion 15 of the eccentric 14, and the eccentric pin at the left face of the eccentric 14, as viewed in FIG. 1, cooperates with an opening in a block 17 fixed to a tube S so that this block 17 reciprocates back and forth during rotation of the eccentric 14. At the start of the rotation the block 17 moves downwardly and the tube 8 which is fixed to the block 17 moves downwardly with the same. The opening of the block 17 to which the eccentric pin of the eccentric 14 extends is long enough in a horizontal direction normal to the plane of FIG. l to accommodate this pin during the entire rotation of the eccentric 14. ln other words, the opening of the block 17 into which the eccentric pin extends has a horizontal length equal at least to the diameter of the eccentric 14.

closes lthe chamber 2a formed in the interior of the piston 2, so that the liquid Within the chamber 2a cannot ilow to the reservoir 5.

The continued rotation of the eccentric 14 causes the annular disc 18 to engage the upper face of the larger piston 6c, this disc 18 being pressed by the spring 20 against the top face of the piston 6a which is xed to the tube 8. The upper end of the spring 20 engages a flange 19 which is fixed to the tube 8 in the manner shown in FIG. l. The piston 6c is urged to the position shown in FIG. l by the spring Z1 located in the interior of the piston 2 which closes the bottom end of the inner member -1, and the continued turning of the eccentric 14 causes the disc 18 to act on the piston 6c so as to lower means shown in FIG. 1.

The tube 8 carriesat its upper end a hollow cylinder V36 of a cross sectional area greater than that of the tube 8. This hollow cylinder 36 extends into the inner chamber 9 of a cylinder 30 which is supported in the interior of the inner member 1 yby the pins 33.V The chamber 9 is closed by a valve which is carried by a member 29 which provides a valve seat for the valve 10. This mem- Y ,ber 29 forms a closure for the cylinder 30 and the interior of the cylinder 30 is sealed at the. element 29 by the slidable sealing ring 31 which is urged upwardly against the "member 29 by the spring 32. Thus, the spring 32 also urges the member 29 upwardly, and an outer ange ofthe member 29 `bears against a wall of a cylindrical member 34 formed with suitable cutouts through which the pins 33 extend. rlhe annular dishr springs 35 located between members 36 and 34 maintain the latter in engagement with the flange of the member 29.

As long as the cylinder 30 remains closed, liquid is displaced from the chamber 9 into `the pressure chamber 7 during upward movement of the tube 8. During turning of the eccentric i4, the downward movement of the tulbe 8 causes the pump means 6 to pump liquid from the reservoirA 5 to the pressure chamber 7, and during upward lmovement liquid is'displaced from the chamber 9 to the pressure chamber 7. During upward'movement of the t-u-be 8, Va return ow of liquid from pressure chamber 7 to the reservoir 5 is prevented by the sealing ring 22, as was pointed out above.

During 'the downward movement of the tube 8 the amount of liquid which ows from the pressure chamber 7' into the chamber 9 is much smaller than the amount of liquid which is pumped by the pump means 6 from the reservoir 5 into the pressure chamber 7. The downward ymovement of the tube 8 is furthermore in the direction of the force of the pressure of the iluid in the chamber 9 which acts on the cross sectional area of the hollow cylinder 36, this cylinder 36 having a larger cross sectional area than the tube 8. As the pressure in the pressure chamber 7 increases during the downward or kpumping stroke of the tube 8, the pressure of the liquid will eventually Ibecome so great that the spring during its compression will be unable to continue to move the piston 6c downwardly, so that at this time the piston tcno Vlonger participates in the pumping action and all the further pumping is done by the small piston 6a. During this pumping the spring 2i) `is compressed during the vdownward strokes of the piston 6a.

i When it Vis, desired to return the apparatus to its collapsedrest position, then from the exterior of the device acrank is placed upon the non-circular portion 24 of the Veccentric 25 so as to turn the latter, and the eccentric pin lofi thelatter extends into an opening ofa block 26 so that thisY block 26 can be reciprocated up and down during turning of the eccentric 25. Of course, the block p 26 is not actually reciprocated, .it is only moved downwardly vto a given position and then upwardly back to Vmember 29 being shown at 29a.

its rest position. The block 26 carries a bottom extension which is located opposite the stem of the valve 10, and it will be noted that a spring 2,7 engages the member 34 and the block 26 to urge the latter upwardly, the upper end of the block 26 carrying a portion which extends slida'bly through a suitable sleeve fixed to the top of the reservoir 5 so as to provide a seal from Ythe outside at this portion of the apparatus. A stack of annular dish springs 28 urges the valve 10 upwardly, yand the downward movement of the block 26 upon turning of the eccentric 25 causes the valve 10 to-be moved downwardly against the force of` the spring 28 so that the valve 10 is moved `in this way to its open position and provides communication between the chamber 9 and the reservoir 5. Thus, the tube 8 together with Vthe cylinder 36 and the Vcylinder 30 and together with the member 29 form a conduit means which provides communication between the reservoir 5 and the pressure chamber 7, and the valve 1t) is capable of closing and opening this conduit means. Since the chamber 9 is at the same pressure as the pressure chamber 7, when the valve 10 is opened the liquid in the pressure chamber 7 can flow into the reservoir 5 which is at less lthan atmospheric pressure, so that the difference between atmospheric pressure and the pressure within the chamber 5 accelerates the ow of liquid from the pressure chamber 7 into the reservoir `5, the atmospheric pressure acting upon the piston 2 of the'Y inner member 1.

In order to accelerate the flowrof pressure liquid from the pressure chamber 7 to the reservoir 5, the eccentric 25 can be turned further to an extent suicient to move the member 29 so ifar into the cylinder 30 that the sealing ring 31 moves out of its bore and thus a larger cross section of ow is provided. It will be noted that the member 29 is provided just above the sealing ring 31 with axially extending grooves which Vcommunicate with the interior of the cylinder 30 when the member 29 is Vmoved downwardly through la suicient distance. This downward movement of the member 2,9 is provided by engagement of the bottom face of the block 26 with the top annular face of the member 29, this annular face of Of course, the spring 32 is compressed during this downward movement of the member 29.

The reservoir 5 is carefully sealed off fromV the outer atmosphere. The piston 2 ofthe inner member 1 carries an additional sealing ring 1'3 to provide a seal from the outer atmosphere.

The upper portion of the inner member 1 carries a suitable itting 12 which is adapted to be connected to a vacuum pump and which carries a non-return valve 11. Thus, when -a vacuum pump is connected to the ditting 12 the force of suction acts to automatically open the valve l11 and the interior of the reservoir 5 may be evacuated.

' Thus, it is possible in this way to obtain by evacuation of the interior of the reservoir 5 a suitable degree of vacuum for an eflicient collapse of the entire device. It is also possible to provide a suitable low pressure in the interior of the reservoir 5 by connecting the tting 1-2 to la vacuum chamber ilarger than the interior of the reservoir 5. The measures taken for providing the vacuum can be used either individually or together.

|FIG. 2 shows an arrangement where a plurality of expandible and collapsible means are operated from a single reservoir and pump assembly. Each of the collapsible and expandible means of FIG. 2 consists in part of an outer tubular member 40 and an inner member 41 slidable along the interior of the member 40, a suitable seal 42 providing a closure of the pressure chamber 45 in the interior of member 40 from the outer atmosphere. The head end 43 of each of the supporting assemblies of FIG. 2 is connected to a guide rail -44 from which the supporting assembly is suspended. The several pressure chambers 4S communicate through conduits 46 and three-way valve 47 with la pump 48, the suction line of which extends almost to the bottom of a reservoir 49 which is closed rolf from the outer atmosphere. Another conduit 50 provides communication between the three-way valve 47 and the reservoir 49. The liquid 51, which may be a suitable oil or the like, is pumped out of the interior of the reservoir 49 by the pump 48 into the chambers 45 when the three-way valve 47 is suitably set. During this operation the several collapsible and expandible means expand so that their length increases between the oor and the rail 44 until the rail 44 is pushed against the ceiling. If the plurality of collapsible and expandible means are suspendedv from the rail 44, this rail 44 is held against the ceiling by van undisclosed structure forming no part of the present invention and then the plurality of collapsible and expandible means expand downwardly until they engage and press against the floor. 0n the other hand, it is possible to simply place the plurality of collapsible and expandible means on the Iiloor and simply to rest the rail `44 on the top ends of the collapsible and expandible means so that when the latter expand they will raise the rail 44 and press it against the ceiling. Of course, with this latter arrangement the plurality of collapsible and expandible means are not suspended from the rail 44.

When it'is desired to cause the plurality of expandible and collapsible means to collapse, the three-way valve 47 is placed in a position which causes the conduits 46 to communicate with the conduit 50, and because of the vacuum formed in the space 54 over the liquid 51 in the interior of the reservoir 49, the liquid ows quickly from the pressure chamber 45 into the reservoir 49 so that the atmospheric pressure forces the plurality of expandible and collapsible means to collapse to their rest position. Where the inner members 41 are suspended from the rail 44 the outer members 40 rise upwardly onto the members 41. Where the members 41 are not suspended, these members 41 move downwardly into the outer members 40, respectively.

In order to increase the degree of vacuum within the reservoir 49, a Vacuum pump 52 communicates with the interior of the reservoir 49, this vacuum pump 52 communicating with ya portion of the conduit '50, and a suitable valve being located in the conduit which leads from the Vacuum pump 52 to the conduit 50.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of supporting arrangements differing from the types described above.

While the invention has been illustrated and described as embodied n hydraulic supporting arrangements, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will `so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications Vwithout omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed Vas new and desired to be secured by Letters Patent is:

1. A hydraulic supporting arrangement to be used as a mine prop or the like comprising, in combination, collapsible and expandible means having a collapsed rest position and an expanded supporting position, said collapsible and expandible means including a pressure chamber to which liquid under pressure flows during expansion of said collapsible and expandible means and from which liquid flows during collapse of said collapsible and expandible means; a reservoir permanently sealed oft from the outer atmosphere and adapted to hold liquid to be supplied to and removed from said pressure chamber; pump means communicating with said reservoir and said pressure chamber for pumping liquid from said'reservoir to said pressure chamber for expanding said collapsible and expandible means, whereby a partial vacuum is created in said reservoir during pumping of liquid therefrom, said pump means including a cylinder formed with an inlet opening communicating with said reservoir and said cylinder being located below thelevel of liquid in said reservoir so that liquid may ilow under the inuence of gravity into said cylinder, a piston movable in said cylinder between a pressure stroke and a suction stroke, a valve cooperating with said inlet opening for opening and closing the same, means Ifor reciprocating said piston, and connecting means for connecting said valve with said reciprocating means for closing said inlet opening dun'ng said pressure stroke and for positively moving said valve during said suction stroke to an open position regardless of .the vacuum in said reservoir; conduit means providing communication between said pressure chamber and reservoir; and valve means in said conduit means for opening and closing the latter, said 'valve means opening said conduit means during collapse of said collapsible and expandible means so that liquid flows `from said pressure chamber through said conduit means to said reservoir during collapse of said collapsible and expandible means.

2. A hydraulic supporting arrangement to be used as a mine prop or the like comprising, in combination, collapsible and expandible means having a collapsed rest position and an expanded supporting position, said collapsible and expandible means including a pressure chamber to which liquid under pressure ilows during expansion of said collapsible and expandible means and from which liquid flows during collapse of said collapsible and expandible means; a reservoir permanently sealed off from the outer atmosphere and adapted to hold liquid to be supplied to and removed from said pressure chamber; pump means communicating with said reservoir and said pressure chamber for pumping liquid from said reservoir to said pressure chamber for expanding said collapsible and expandible means, whereby a partial vacuum is created in said reservoir during pumping of liquid therefrom, said pump means including a cylinder formed with an inlet opening communicating with said reservoir and said cylinder 'being located below the level of liquid in said reservoir so that liquid may ow under the influence of gravity into said cylinder, a piston movable in said cylinder between a pressure stroke and a suction stroke, a valve cooperating with said inlet opening for opening and closing the same, means vfor reciprocating said piston, and connecting means for connecting said valve with said reciprocating means for closing said inlet opening during said pressure stroke and for positively moving said valve during said suction stroke to an open position regardless of the vacuum in said reservoir; conduit means providing communication between said pressure chamber and reservoir; valve means in said conduit means for opening and closing the latter, said valve means opening said conduit means during collapse of said collapsible and eX- pandible means so that liquid flows from said pressure chamber through said conduit means to said reservoir during collapse of said collapsible and expandible means, whereby the partial vacuum in said reservoir will provide for a suction of the liquid from said pressure chamber to said reservoir to expedite the collapse of said collapsible and expandible means; and means communicating with said reservoir for increasing the partial vacuum in the interior thereof.

3. A hydraulic supporting arrangement to be used as a mine prop or the like comprising, in combination, collapsible and expandible means having a collapsed rest position and an expanded supporting position, said collapsible and expandible means including a pressure chamlber to -which liquid under pressure flows during expansion of said collapsible and expandible means and from which liquid flows during collapse of said collapsible and expandible means;V a reservoir permanently sealed oif from the outer atmosphere and adapted to hold liquid to be supplied to and removed from saidn pressure chamber; pump. means communicating wtih said reservoir and said pressure chamber for pumping liquid from said reservoir to said pressure chamber Ifor expanding said collapsible and expandible means, whereby a partial vacuum is created in said reservoir during pumping of liquid therefrom, said pump means including a cylinder formed with an inlet opening communicating With said reservoir and said cylinder lbeing located below the level of liquid in said reservoir so that liquid may ow under the influence of gravity into said cylinder, a piston movable in said cylinder between a pressure stroke and a suction stroke, a valve cooperating with said inlet opening for opening and closing the same, means for reciprocating said piston, and connecting means for connecting said valve with said reciprocating means for closing said inlet opening during said pressure stroke and for positively moving said valve during said suction stroke to an open position regardless of the vacuum in said reservoir; conduit means providing communication between said pressure chamber and reservoir; valve means in said conduit means for opening and closing the latter, said valve means opening said conduit means during collapse of said collapsible and expandible means so that liquid flows from said pressure chamber through said conduit means to said reservoir during collapse of said collapsible and expandible means, whereby the partial vacuum in said reservoir will provide for a suction of the liquid from said pressure chamber to said reservoir to expedite the collapse of said collapsible and expandible means; and means communicating with said reservoir for increasing the partial vacuum in the interior thereof, said latter means being a vacuum pump.

4. A hydraulic upright supporting arrangement to be used as a mine prop or the like comprising, in com-bina-l tion, collapsible and eXpandible means including a pressure chamber located at the bottom region of the supporting arrangement to which liquid is supplied during expansion of said collapsible and expandible means and from which liquid ilows during contraction of said collapsible and expandible means; a reservoir permanently sealed ol Afrom the outer atmosphere and formed by a hollow portion of said collapsible and expandible means, said reservoir being located above saidpressure chamber'and being adapted to' contain a liquid to be supplied to said pressure chamber; pump means located in the interior of said collapsible and expandible means between and communicating with said pressure chamber andsaid reservoir fory pumping liquid from said reservoir to'rsaid pressure chamber for expanding said collapsible and expandible means, whereby a partial vacuum is createdV in said reservoir during pumping of liquid therefrom,said pump means including a cylinder'formed with an inlet opening communicating with said reservoir, a piston movable in said cylinder in one direction along a pressure stroke and a suction stroke, valve means cooperating with said inlet opening for opening and closing the same, means for reciprocating said piston in said cylinder, and means connecting said valve means to said reciprocating means for closing said inlet opening lduring the movement of said piston along the pressure stroke thereof and for positively moving said valve means to an open position during the suction stroke regardless of the vacuum in said reservoir; conduit means communicating with said reservoir and said pressure chamber; :and additional valve means cooperating With said conduit means for opening and closing the latter, so that when said additional valve means opens said conduit means liquid may flow from said pressure chamber to said reservoir to collapse said collapsible and expandible means, whereby the partial vacuum in said reservoir ywill provide for a suction of the liquid from said pressure chamber to said reservoir to expedite the collapse of said collapsible and expandible means.

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